Method for reversibly mounting a device wafer to a carrier substrate

Abstract

New temporary bonding methods and articles formed from those methods are provided. The methods comprise bonding a device wafer to a carrier wafer or substrate only at their outer perimeters in order to assist in protecting the device wafer and its device sites during subsequent processing and handling. The edge bonds formed by this method are chemically and thermally resistant, but can also be softened, dissolved, or mechanically disrupted to allow the wafers to be easily separated with very low forces and at or near room temperature at the appropriate stage in the fabrication process.

We claim: 
     
       1. A temporary bonding method comprising:
 providing a stack comprising:
 a first substrate having a back surface and a device surface, said device surface having a peripheral region and a central region, wherein said device surface comprises an array of devices selected from the group consisting of integrated circuits; MEMS; microsensors; power semiconductors; light-emitting diodes; photonic circuits; interposers; embedded passive devices; and microdevices fabricated on or from silicon, silicon-germanium, gallium arsenide, and gallium nitride; 
 a second substrate having a carrier surface; and 
 an edge bond bonded to said peripheral region and to said carrier surface, said edge bond being absent from said central region so as to form a fill zone, wherein said edge bond is formed from a material comprising monomers, oligomers, or polymers selected from the group consisting of epoxies, acrylics, silicones, styrenics, vinyl halides, vinyl esters, polyamides, polyimides, polysulfones, polyethersulfones, cyclic olefins, polyolefin rubbers, and polyurethanes; and 
 an amorphous polymeric fill material in said fill zone, said fill material having an adhesion strength of less than about 50 psig as determined by ASTM D4541/D7234, wherein said edge bond has an adhesion strength that is at least about 0.5 psig greater than said fill material adhesion strength; 
 
 separating said first and second substrates, wherein prior to said separating, said edge bond is exposed to solvent to dissolve said edge bond, or said edge bond is mechanically disrupted using laser ablation, plasma etching, or water jetting. 
 
     
     
       2. The method of  claim 1 , wherein said second substrate comprises a material selected from the group consisting of silicon, sapphire, quartz, metal, glass, and ceramics. 
     
     
       3. The method of  claim 1 , said device surface comprising at least one structure selected from the group consisting of: solder bumps; metal posts; metal pillars; and structures formed from a material selected from the group consisting of silicon, polysilicon, silicon dioxide, silicon (oxy)nitride, metal, low k dielectrics, polymer dielectrics, metal nitrides, and metal silicides. 
     
     
       4. The method of  claim 1 , wherein said fill material presents a first surface in contact with said carrier surface, and a second surface in contact with said device surface, said fill material being a uniform material from said first surface to said second surface. 
     
     
       5. The method of  claim 1 , wherein said fill material presents a first surface and a second surface, said stack further comprising a second layer in contact with one of said first and second surfaces, the other of said first and second surfaces being in contact with one of said carrier surface and said device surface. 
     
     
       6. The method of  claim 5 , wherein said second layer is selected from the group consisting of a low adhesive strength layer, a polymeric layer, and a surface modification of said carrier surface or of said device surface. 
     
     
       7. The method of  claim 6 , wherein said second layer is in contact with said carrier surface. 
     
     
       8. The method of  claim 1 , wherein said edge bond has a width of from about 2 mm to about 15 mm. 
     
     
       9. The method of  claim 1 , wherein said fill material comprises monomers, oligomers, and/or polymers selected from the group consisting of cyclic olefins and amorphous fluoropolymers. 
     
     
       10. The method of  claim 1 , further comprising subjecting said stack to processing selected from the group consisting of back-grinding, chemical-mechanical polishing, etching, metal and dielectric deposition, patterning, passivation, annealing, and combinations thereof, prior to separating said first and second substrates. 
     
     
       11. The method of  claim 1 , wherein said separating comprises applying a low force to at least one of said first and second substrates so as to pull them apart. 
     
     
       12. The method of  claim 1 , wherein said edge bond remains stable at temperatures up to about 350° C. 
     
     
       13. A temporary bonding method comprising:
 providing a stack comprising:
 a first substrate having a back surface and a device surface, said device surface having a peripheral region and a central region; 
 a second substrate having a carrier surface, wherein said second substrate comprises a material selected from the group consisting of silicon, sapphire, quartz, metal, glass, and ceramics; and 
 an edge bond bonded to said peripheral region and to said carrier surface, said edge bond being absent from said central region so as to form a fill zone, wherein said edge bond is formed from a material comprising monomers, oligomers, or polymers selected from the group consisting of epoxies, acrylics, silicones, styrenics, vinyl halides, vinyl esters, polyamides, polyimides, polysulfones, polyethersulfones, cyclic olefins, polyolefin rubbers, and polyurethanes; and 
 an amorphous polymeric fill material in said fill zone, said fill material having an adhesion strength of less than about 50 psig as determined by ASTM D4541/D7234, wherein said edge bond has an adhesion strength that is at least about 0.5 psig greater than said fill material adhesion strength; 
 
 separating said first and second substrates, wherein prior to said separating, said edge bond is exposed to solvent to dissolve said edge bond, or said edge bond is mechanically disrupted using laser ablation, plasma etching, or water jetting. 
 
     
     
       14. The method of  claim 13 , said device surface comprising at least one structure selected from the group consisting of: solder bumps; metal posts; metal pillars; and structures formed from a material selected from the group consisting of silicon, polysilicon, silicon dioxide, silicon (oxy)nitride, metal, low k dielectrics, polymer dielectrics, metal nitrides, and metal silicides. 
     
     
       15. The method of  claim 13 , wherein said fill material presents a first surface in contact with said carrier surface, and a second surface in contact with said device surface, said fill material being a uniform material from said first surface to said second surface. 
     
     
       16. The method of  claim 13 , wherein said fill material presents a first surface and a second surface, said stack further comprising a second layer in contact with one of said first and second surfaces, the other of said first and second surfaces being in contact with one of said carrier surface and said device surface. 
     
     
       17. The method of  claim 16 , wherein said second layer is selected from the group consisting of a low adhesive strength layer, a polymeric layer, and a surface modification of said carrier surface or of said device surface. 
     
     
       18. The method of  claim 17 , wherein said second layer is in contact with said carrier surface. 
     
     
       19. The method of  claim 13 , wherein said edge bond has a width of from about 2 mm to about 15 mm. 
     
     
       20. The method of  claim 13 , wherein said fill material comprises monomers, oligomers, and/or polymers selected from the group consisting of cyclic olefins and amorphous fluoropolymers. 
     
     
       21. The method of  claim 13 , further comprising subjecting said stack to processing selected from the group consisting of back-grinding, chemical-mechanical polishing, etching, metal and dielectric deposition, patterning, passivation, annealing, and combinations thereof, prior to separating said first and second substrates. 
     
     
       22. The method of  claim 13 , wherein said separating comprises applying a low force to at least one of said first and second substrates so as to pull them apart. 
     
     
       23. A temporary bonding method comprising:
 providing a stack comprising:
 a first substrate having a back surface and a device surface, said device surface having a peripheral region and a central region; 
 a second substrate having a carrier surface; and 
 an edge bond bonded to said peripheral region and to said carrier surface, said edge bond being absent from said central region so as to form a fill zone, wherein said edge bond is formed from a material comprising monomers, oligomers, or polymers selected from the group consisting of epoxies, acrylics, silicones, styrenics, vinyl halides, vinyl esters, polyamides, polyimides, polysulfones, polyethersulfones, cyclic olefins, polyolefin rubbers, and polyurethanes; and 
 an amorphous polymeric fill material in said fill zone, said fill material having an adhesion strength of less than about 50 psig as determined by ASTM D4541/D7234, wherein said edge bond has an adhesion strength that is at least about 0.5 psig greater than said fill material adhesion strength; 
 
 subjecting said stack to processing selected from the group consisting of back-grinding, chemical-mechanical polishing, etching, metal and dielectric deposition, patterning, passivation, annealing, and combinations thereof; and 
 separating said first and second substrates, wherein prior to said separating, said edge bond is exposed to solvent to dissolve said edge bond, or said edge bond is mechanically disrupted using laser ablation, plasma etching, or water jetting. 
 
     
     
       24. The method of  claim 23 , said device surface comprising at least one structure selected from the group consisting of: solder bumps; metal posts; metal pillars; and structures formed from a material selected from the group consisting of silicon, polysilicon, silicon dioxide, silicon (oxy)nitride, metal, low k dielectrics, polymer dielectrics, metal nitrides, and metal silicides. 
     
     
       25. The method of  claim 23 , wherein said fill material presents a first surface in contact with said carrier surface, and a second surface in contact with said device surface, said fill material being a uniform material from said first surface to said second surface. 
     
     
       26. The method of  claim 23 , wherein said fill material presents a first surface and a second surface, said stack further comprising a second layer in contact with one of said first and second surfaces, the other of said first and second surfaces being in contact with one of said carrier surface and said device surface. 
     
     
       27. The method of  claim 26 , wherein said second layer is selected from the group consisting of a low adhesive strength layer, a polymeric layer, and a surface modification of said carrier surface or of said device surface. 
     
     
       28. The method of  claim 27 , wherein said second layer is in contact with said carrier surface. 
     
     
       29. The method of  claim 23 , wherein said edge bond has a width of from about 2 mm to about 15 mm. 
     
     
       30. The method of  claim 23 , wherein said fill material comprises monomers, oligomers, and/or polymers selected from the group consisting of cyclic olefins and amorphous fluoropolymers. 
     
     
       31. The method of  claim 23 , wherein said separating comprises applying a low force to at least one of said first and second substrates so as to pull them apart.